Presence of heavy metals such as mercury in fluid streams can cause problems with downstream processing units as well as health and environmental issues if released as waste. Government regulations also limit amount of the mercury, for example, that may be discharged. Exemplary sources of the fluid streams containing one or more of the heavy metals include produced hydrocarbon gases, flue gas from combustion of fossil fuels, and gas mixtures generated with gasification facilities.
Treating gases upon recovery from hot underground formations and separation from liquid hydrocarbons provides an example of when desirable to have treatment to avoid treating of multiple gas streams and downstream contamination. Mercury removal from the streams presents problems with previous techniques. Many sorbents utilized for mercury removal require undesirable cooling of the streams for mercury retention by the sorbents.
Further, prior sorbents impregnated with metal provide limited stability. Such sorbents in particular fail to provide the metal in a single compositional phase that is stable. Even if the metal is present for example in a stabilized phase, such as metal sulfide, these sorbents include some of the metal in an undesirable phase, such as elemental form or as metal oxide, which inhibits sorbent activity.
Therefore, a need exists for compositions suitable for treatment of fluids to remove heavy metals and methods of preparing and using the compositions.